Tennis racket with pneumatic tightener



March 1936- A. RAUCH ET AL 2,034,444

TENNIS RACKET WITH PNEUMATIC TIGHTENER Filed March 8, 1954 2Sheets-Sheet 2 Patented Mar. 17, 1936 TENNIS RACKET WITH PNEUMATICTIGHTENER Antonin Ranch and Vaclav Smolik, Prague, CzechoslovakiaApplication March 8, 1934, Serial No. 714,694 In Czechoslovakia March30, 1932 1 Claim.

This invention relates to a tennis racket with pneumatic tightening ofthe gut stringing carried out according to the invention in such amanner, that round the fixed, inner frame and handle of the racket, oneor preferably two parallel rubber tubes are located, filled withcompressed air; these tubes consist either from one single piece, orconveniently of two interconnected air pipes, or tubes, connected ortied together by a ligament. The stringing of the racket is heldtogether and adjusted by the usual means, such as hooks, or thethreading through of the racket frame etc., to the outer rim of theracket frame, which consists of several independent segments, movablerespectively to each other and to the inner frame, and is tightened orloosened by inflating or deflating the air tubes.

On the accompanying drawings an embodiment of the invention is given byway of example, with the corresponding details and alternative solutionsthereof. Fig. 1 shows schematically the elevation of the racket insection along line II in Fig. 2; Fig. 2 is a side-view of the tennisracket with a double rubber tube, Fig. 3 is a longitudinal axial sectionled through the handle of the racket with the gear, connecting the airpipes and showing the relief valve and the piston, located nearly in itsupper position, omitting the frame. Fig. 9 shows a detailed side-view ofthe racket part of Fig. 3, Figs. 4 to 8 show five different devices forholding the gut stringing on the pneumatically tightened frame, all incross section.

The tennis racket consists, according to the invention, of a stiff innerframe [6 of the usual oval shape, which is provided below with aforkextension l2, to which a hollow handle I4 is connected. All roundthe outer circumference of this inner frame In a slot I6 runs, having arounded canal section (Figs. 4 to '7) or two similar slots runningparallel to each other (Figs. 2 and 8), in each of which an elastic airtube l8 of usual circular cross section is placed. On the outercircumference of the stiff frame l8 and beyond the tube 18, or bothparallel air tubes I8 is set a number of segment rim-pieces 26 along thetubes, either between both lateral parallel flanges l6 (Figs. 1, 2, 4and 5) of the inner frame ID or themselves provided with parallelflanges 28', which cover the tube l8 laterally, as well as the stiffinner frame l0.

Therubber tube I8, or each of both tubes l8 lying side by side, isdivided on the top, i. e. at the point opposite to the handle l4; eachtube consists thus of two branches, the ends of which may be tightenedand provided with a ligament 24. The other ends of the tubes areconnected together and fitted to a common piping 26, extending betweenthe sideplates I2 of the handle ID and reaching to a connecting pipe 28,fitted to a relief valve 38 (Fig. 3), serving to close the tube in a wayas described below.

The connection of the tube 26 with the pipe 28 is eifected by means of aconical screw-socket 32 provided with an outer thread (Fig. 9), on whicha tightening nut 34 may be screwed. This nut ensures an absolutely fixedand immovable connection between the tube extension 26 and the valvepipe 28. The valve needle 36 of the relief valve 36 in the pipe 28extends up to the middle of the hollow part 38 of the handle I l, wherea piston 46 is placed; the piston rod 62 of the piston is terminated onits outer free end by a handle 44, which may be fixed in the normalposition by means of a bayonet fastening 46. Inside the hollow pistonrod 42 of the piston, a spindle 48 (Fig. 3) is provided, the inner endof which is flattened and located in the space above the piston, Whilstits outer end is provided with a button 52, set in a depression 54 ofthe piston handle. Under the button of this spindle a return safetyspring 56 is placed in the said depression for a purpose hereinafterdescribed.

The racket strings 58 of the gut stringing may be fixed to the outersegmental rim parts 26 of the frame in various manners, as may be seenin Figs. 1, 2, 4 to 8. In the alternative arrangements according toFigs. 1, and 2 the gut stringing is threaded through apertures in themovable parts of the rim 28; these strings are suspended on a number ofhooks 68 on the part of the frame lying at the top of the handle, whilstthe outer free parts of the rim 28 are interrupted at this place toenable the removal of the tubes from inside the frame by loosening theligaments 24; the ligaments serve besides to pull these tubes back intothe frame groove after effecting the repair or exchange thereof.

In the alternative according to Fig. 4, the stringing 58 is led over asmall pulley Wheel 62 suspended freely on a wire stirrup 64, adjusted ina transverse slot 66 of the outer rim 28 of the racket frame.

According to Fig. 5, the gut of the racket stringing is directlythreaded through a similar transverse slot 66.

In the arrangement shown in Fig. 6, the pulley wheel 62 is placed on atransverse spindle 68, adjusted on both lateral flanges 26 of thecorresponding rim 2!) of the frame.

In the alternative mode according to Fig. 7,

both lateral flanges 20 of the rim segments 20 forming the outer frameof the racket are bent inwards; the flattened base 10 of the suspensionhook 12 is held in the required position by the ends 20" of these bentflanges.

In the alternative shown in Fig. 8 the hooks M are led through the fixedinner and the movable outer frame; these hooks are held in the centralgroove running round the circumference of the rim either by means of aneye with a pin or by any other suitable manner.

The arrangement as described above enables us to adjust the requiredtension of the gut stringing of the racket at any time; the racketstringing remaining elastic, whatever the degree of tightening may be,owing to the elasticity of the inflated rubber tube, which at the end ofthe game may be eased or deflated by merely pressing the button 52together with the central inner spindle 48 inside the racket handle,thus opening the relief valve 36, through which the air may be entirelyor partly let out of the rubber tube or tubes 18; the tension of the gutbeing thereby eased. A further advantage of the arrangement is that whenthe tubes l8 are deflated, the racket may be strung or restrung withoutspecial tension or tensioning devices as restringing is carried outpreferably when the pressure in the tubes is eased, contrarily to thehitherto current procedure. The rubber tubes may even be completelyremoved from off the racket when adjusting the gut stringing, in themanner referred to above.

What we claim is:

A tennis racket comprising a handle, a substantially oval frame attachedto said handle, a pair of rubber tubes, a connecting tube positioned insaid handle, a pump comprising a cylinder, a piston and a piston rod allpositioned in said handle, a valve connected to said connecting tube andsaid pump cylinder and means extending through said piston rod foropening said valve to reduce the pressure in said rubber tubes.

AIEITONI'N RAU H. VACLAV SMOLIK.

